ASA 125th Meeting Ottawa 1993 May

2pPP17. Cross-modal enhancement of repetition detection for very long period recycling frozen noise.

Dept. of Psychol., Univ. of Wisconsin---Milwaukee, Milwaukee, WI 53201

Guttman and Julesz [J. Acoust. Soc. Am. 35, 610 (1963)] reported that recycling of frozen noise segments can be readily detected for periods up to 1 s and can be detected with difficulty for periods of 2 s. These experiments demonstrate that this limit can be exceeded with ease. It was found that a cross-modal cue (e.g., a light flash) presented synchronously with a randomly selected point in a 10-s recycled frozen noise allows listeners to tap accurately at the repetition rate when the recycled noise is subsequently presented without the cue---even following delays of 24 h or more. Two mechanisms for the effect of cueing are suggested: (1) it provides an accurate time base for determining when repetition of salient events will occur; (2) cross-modality attentional effects highlight auditory events concurrent with the cue. Experiments distinguishing between these two mechanisms will be discussed along with other aspects of the effect. [Work supported by NIH.]